Polishing the sun

15th of April 2010

Germany has seen a significant rise in the number of solar panels being installed - and they all need cleaning. ECJ correspondent Thomas Schulte-Marxloh reports.

Germany is not famous for its sunny weather in the first place, and for many Germans the idea of employing solar energy in Germany seemed as odd as using water power in the desert. That was many years ago. Meanwhile, the increasing importance of regenerative energy, environmental protection, the green house effect as well as technological progress resulted in a rapidly growing share of this environ-mentally friendly energy.

By the end of 2010 the estimated total amount of solar energy will be 10 GW - and that figure is expected to grow. A large amount of solar energy is produced by solar cells which are mounted on roofs of private houses or commercial buildings of companies demonstrating their environmental consciousness. One of the advantages of modern solar cells is the so-called self-cleaning effect which promises easy care – however, that is theory.

A low roof pitch, for example, or when the larger side of framed solar cells faces up-wards, the very frame of a module, dust from farms, industry or construction sites, pollen, and last but not least bird faeces – actually, the most persistent pollution – can mean a severe restriction of the easy-care promise and performance of the solar cell. Also moss growing on the edges of the modules has to be removed.

The cleaning of solar cells means some challenges – not only in terms of safety and equipment – even for contract cleaning companies. Mean-while, a growing number of companies offer respective cleaning services for private persons and industry.

Solar cells are made of glass and delicate items. Also any contact with electrical parts can be dangerous, in particular when water is involved. High pressure cleaning devices can damage the modules as well as aggressive cleaning agents.

Many companies do not use detergents at all and clean with purified water. In general it is important to avoid any residues (scale, detergent layers, etc) on the cells which might hinder performance. According to producers of solar cells rapid changes of temperature should not harm the glass panels. Nonetheless, cleaning in blazing sun is not recommended.

Equipment is also important as working on a roof can be dangerous: either respective safety instructions have to be followed or one avoids stepping on the roof at all and uses safe devices like scaffoldings, mobile hydraulic lifts and/or a pole system to apply the detergent or/and water to the panel. Apart from detergents the market offers several purified water systems which are very suitable for cleaning solar cells. This means some investment in work equipment.

With the rise of solar energy in Germany new business opportunities have emerged. Although many private house-holds would not even think of employing a contract cleaning company for their living room, it seems to be too adventurous to clean the solar equipment on the roof privately - and professional help is welcome.